In the case of Latin, the word for fox is vulpus, which is a direct evolution of the indo-european root. In this case, the problem is less of a taboo word than of an appropriation of the sense to a different animal.
There's a comment on the story itself that says this, with a reply pointing out that it's not "vulpus" but "volpes", which evolved from a slightly different proto-Indo-European root.
